Photosensitive inks and coatings are formulated to react to radiant energy in the ultraviolet range (250 to 400 nm) for accelerated curing. The inks and coatings are applied, in a printing press for example, to moving webs or sheets. The webs or sheets are then directed through a beam of radiant energy generated by a curing device to subject the inks and coatings to ultraviolet rays. Curing devices typically include a high intensity source of radiant energy to generate sufficient amounts of ultraviolet radiation for rapid curing of the photosensitive inks and/or coatings applied to the moving substrate. Curing devices typically include a reflector positioned adjacent the lamp to redirect a portion of the radiant energy to form a focused beam.
The radiant energy generated by the high intensity light source, however, includes heat generating rays of infrared radiation and visible light rays in addition to the desired ultraviolet rays. If left untreated, the amount of heat contained in the infrared and visible light rays could damage many substrates, such as heat shrinkable labeling used for food and beverage containers, for example. U.S. Pat. No. 4,864,145 discloses a curing device having a high intensity, medium pressure, mercury vapor lamp and a liquid cooled reflector. The beam is directed through a liquid filled filtering chamber to remove infrared radiation from the beam. The beam is then redirected, through a filtering pane, by an angled reflector. U.S. Pat. No. 5,321,595 discloses a curing device having liquid filled tubes for filtering infrared radiation from a radiant energy beam.
It is sometimes necessary to stop a printing press to make adjustments, for example. Prolonged exposure to the radiant energy from a curing device during a stoppage could be damaging to many substrates. U.S. Pat. No. 5,722,761, discloses a curing device having reflector members that can be pivoted to impinge on a portion of the radiant energy beam thereby preventing passage of the beam portion to the substrate.